Various types of herbicides have been developed heretofore in the fields of agriculture and horticulture, greatly contributing to the elimination or reduction of weeding work. Among these herbicides, there are known Paraquat (i.e. 1,1'-dimethyl-4,4'-bipyridiniumdichloride) and Glyphosate (i.e., N-phosphonomethylglycine) as useful compounds, particularly as nonselective post-emergence herbicides. However, these conventional herbicides, although markedly effective as herbicides under some conditions, suffer numerous defects when used in some other situations. Thus, it has been desired to provide new herbicides free from such drawbacks. For example, "Paraquat" is a fast-acting contact herbicide, but has herbicidal activity only for a short period of time and high toxicity. "Glyphosate" is a post-emergence translocation herbicide and maintains herbicidal activity for a prolonged period of time. But it has the defects of being slow-active and less effective in killing perennial broad-leaf weeds.